The study will evaluate the efficacy and safety of budesonide nebulizing suspension, in children between the ages of 6 months and 8 years with moderate to severe asthma. The trial is a double blind placebo- controlled, dosage, efficacy and safety trial. During the course of treatment, patients will be evaluated with pulmonary function tests and screening laboratory studies. Additionally, assessment of hypothalamic-pituitary-adrenal axis function will be done with baseline laboratory studies, including Cortosyn stimulation testing.